1. Field of the Invention
The present invention is directed generally to making latent fingerprints visible and semipermanent. More specifically, the present invention is related to a method and apparatus for vaporizing a liquid cyanoacrylate composition that polymerizes upon contact with the fingerprint.
2. Background Information
It is known that cyanoacrylate can be used to develop fingerprints through a polymerization reaction in which cyanoacrylate vapor contacts a latent fingerprint. Chemicals in the fingerprint cause the polymerization of the cyanoacrylate resulting in an enhanced visual image of the print.
U.S. Pat. Nos. 5,424,092; 5,348,759; 5,342,645; 4,613,515; 4,550,041; 4,461,235; and 4,407,842 relate to apparatus and methods for developing latent fingerprints using cyanoacrylate. U.S. Pat. Nos. 4,700,657; 4,461,235 and 4,294,383 disclose closed fingerprint detection systems using cyanoacrylate. U.S. Pat. Nos. 5,462,597 and 5,395,445 disclose methods for detecting fingerprints on skin.
The '092 and '759 patents, for example, disclose a housing containing a thermally stable porous material that is impregnated with a liquid cyanoacrylate, which is allowed to cure. A portable heating device such as a propane torch can be used to vaporize the cyanoacrylate, which is propelled toward the object to be tested by the torch exhaust.
The '515, '041 and '235 patents disclose a method and apparatus whereby vapors are generated from a thin film of a storage stable cyanoacrylate monomer composition that has been complexed to render the composition substantially non-flowable. An envelope package for the monomer composition may be peeled open to expose the inner surfaces coated with a film of the composition.
The methods and apparatus described above are slow to display the fingerprints and, in some instances, require that the target area be placed in a sealed container. Accordingly, there is a need for a portable, rapid, simple and safe method for rendering latent fingerprints detectable.